1. Field of the Invention
This invention relates to the composition of cleaning blocks to be placed in the tanks of automatic flush toilets, their use, and their manufacture.
2. Statement of Related Art
For automatically cleaning flush toilets operating with a reservoir tank, it has long been standard practice to use block-form cleaners which are placed or suspended in the cistern and which release their active ingredients to the flushing water over a prolonged period. Products which may be used without further aids, i.e. which may be directly thrown into the cistern, are particularly simple to handle. Cleaners such as these, which are generally in the form of blocks or tablets, have adequate useful lives by virtue of their low dissolving rate alone. Examples of products such as these can be found in U.S. Pat. Nos. 3,540,899; 4,043,931; and 4,460,490; and in British patent document No. 2,061,996.
However, none of the known products is free from disadvantages, whether too high a dissolving rate, inadequate cohesion or inadequate adherence to the cistern wall, so that the cleaners are partially entrained by the water or totally undissolved, or demonstrate inadequate cleaning power through uneven product release.